Copper-refining apparatus and the like

ABSTRACT

THIS INVENTION IS ESPECIALLY CONCERNED WITH APPARATUS FOR THE PRODUCTION OF REFINED COPPER FROM SCRAP AND/OR OTHER IMPURE COPPER HAVING HIGH LEAD AND/OR TIN CONTENT WHEREIN SLAG FORMERS MAY BE SELECTED FROM COMPOUNDS OF BORATES, SILICATES, PHOSPHATES AND ALKALI OXIDES.

P 2 9 w. B. GREENBERG 3,606,986

COPPER-REFINING APPARATUS AND THE LIKE 3 SheetsSheet l /A'V4/7'0PWILLIAM B. GREENBERG W/6 km A TOIPAM-T Sept. 21, 1971 w. B. GREENBERGCOPPER-REFINING APPARATUS AND THE LIKE Original Filed Feb. 5, 1968 3Sheets-Sheet 3 M'KSWIJK WILLIAM B. GREEN BERG Wi m ep 21,1911 w. B. GEENBERG 3,606,986

COPPER-REFINING APPARATUS AND THE LIKE Original Filed Feb. 5, 1968 sSheets-Sheet 1s llltW/Uk WILLIAM B. GREENBERG 3,606,986 COPPER-REFININGAPPARATUS AND THE LIKE William B. Greenberg, 1510 Brinton Park Drive,Wynnewood, Pa. 19096 Original application Feb. 5, 1968, Ser. No.702,973, now Patent No. 3,561,952, dated Feb. 9, 1971. Divided and thisapplication Aug. 7, 1970, Ser. No. 61,986

Int. Cl. C22b 15/06 US. Cl. 26636H 7 Claims ABSTRACT OF THE DISCLOSUREThis invention is especially concerned with apparatus for the productionof refined copper from scrap and/or other impure copper having high leadand/or tin content wherein slag formers may be selected from compoundsof borates, silicates, phosphates and alkali oxides.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is a divisionof my copending application Ser. No. 702,973 filed Feb. 5, 1968 and nowPat. No. 3,561,952.

BACKGROUND OF THE INVENTION As is well known to those versed in the art,the refining of copper scrap, and especially of No. 2 copper scrap, torelatively low levels of tin and lead, particularly the latter, has beenuneconomical in this country. The time and expense involved in therefinement of copper scrap, say No. 2 copper scrap to a lead content upto and including 004% has heretofore been too time consuming andexpensive in the United States to meet lowercost operations in foreigncountries.

SUMMARY OF THE INVENTION Accordingly, it is an important object of thepresent invention to provide apparatus for refining copper scrap, whicheffects substantial economies in labor, time, and cost and maintenanceof equipment, so that the refinement of even No. 2 copper scrap to leadcontent up to and including .004% is economically feasible in the UnitedStates.

It is still a further object of the present invention to provide uniqueimprovements in the refinement of copper scrap including particularcombinations of furnace linings and slag-forming materials to achieve ahigh degree of refinement at considerable savings in time and cost.

It is still a further object of the present invention to provideapparatus for use in copper-scrap refining wherein the apparatus isrelatively simple in structure while capable of performing multipleoperations in the scrap-refining method of the instant invention.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawings,which form a material part of this disclosure.

The invention accordingly consists in the features of construction, andcombinations and arrangements of elements and method steps, which willbe exemplified in the following description, and of which the scope willbe indicated by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic longitudinalelevational view showing apparatus of the present invention in an earlystage of the instant method.

FIG. 1a is a transverse sectional view taken generally along the line1a1a of FIG. 1.

' United States Patent ICC FIG. 2 is a diagrammatic longitudinalsectional elevational View illustrating a slightly later stage in theinstant method.

FIGS. 3-9 are longitudinal sectional elevational views showingsuccessive stages in operation of the instant method.

FIG. 10 is a transverse sectional view showing another embodiment offurnace constructed in accordance with the teachings of the presentinvention.

FIG. 11 is a longitudinal sectional elevational view showing anotherembodiment of furnace constructed in accordance with the teachings ofthe present invention.

FIGS. 12 and 13 are transverse sectional elevational views takengenerally along the lines 12 and 13, respectively, of FIG. 11.

FIG. 14 is a diagrammatic side elevational view of the furnace of FIG.11.

FIG. 15 is a longitudinal sectional elevational view of the furnace ofFIG. 11, illustrating a stage in the method of the present invention.

FIG. 16 is a longitudinal sectional elevational view similar to FIG. 15,illustrating a later stage in practice of the instant method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The disclosure of the instantinvention relates to the refinement of various types of copper scrap torelatively low levels of tin and lead while, in some cases, achievingcommercially valuable by-products such as bronze, and effecting reuse ofslag to considerably reduce costs.

In general, copper scrap at the refining stage may be subdivided intoNo. 2 copper scrap or blister copper which includes substantial amountsof both lead and tin, each usually being present by over /2% and insubstantially equal amounts. Another type of copper scrap at therefining stage is designated black copper and is relatively high in leadcontent, generally about 3 /2% to 7% lead, and also relatively high intin content, say on the order of 3 /2% to 7% tin. These different typesof copper scrap may all be refined by slight variations in the instantinvention.

In a furnace capable of generating heat sufficient to melt copper, thereis provided a furnace lining of high acidity. The lining material hasbeen found to comprise at least by weight of SiO In the same furnacethere may be provided a separate section of reducing lining, say ofcarbon, carbon-bonded silicon carbide, clay and graphite, or othersuitable reducing material. If desired, a separate reducing furnace maybe employed.

In the embodiment shown in FIGS. 19, there is a furnace generallydesignated 20 which may be of an elongate, generally cylindricalconfiguration having its opposite ends open, as at 21 and 22. Thefurnace 20- may be subdivided interiorly by a pair of spaced, transversepartitions or walls 23 and 24, which serve to divide the interior of thefurnace into a plurality, namely three interior compartments, sectionsor chambers. An intermediate chamber or section 25 is located betweenthe barriers 23 and 24, while an end chamber or section 26 is locatedbetween the barrier 23 and its adjacent end opening 21, while anadditional end chamber or section 27 is located between the barrier 24and its adjacent end opening 22. The intermediate chamber or section 25is lined with an acid material, as at 30, which may be at least 70% byweight of S10 The end chambers or sections 26 and 27 are each providedwith a reducing lining, as at 31 and -32, which may be formed of carbon,carbon-bonded silicon carbide, clay and graphite, or other suitablereducing material or refractory.

A furnace-mounting means is generally designated 35, see FIGS. 1 and laand is adapted to mount the furnace 20 for both tilting movement about atransverse axis and rotative movement about a longitudinal axis. Forexample, the mounting means 35 may include a frame 36 about the medialregion of the furnace 20 and provided on opposite sides with arcuatespur-gear sectors 37, each of which rests on a pair of rotary pinions38, the pinions 'being mounted on pedestals 39 upstanding from asupporting surface or floor 40. By powering one or more of the pinions38, the sectors 37 are caused to rotate and effect longitudinal tiltingof the furnace 20.

In addition, the frame 35 may be provided a plurality of longitudinallyextending rollers 41 rotatably supporting the cylindrical furnace 20 foraxial rotation of the latter. Thus, the furnace is mounted for bothaxial and transverse rotative movement. Of course, suitable power andcontrol means may be associated with the mounting means 35 to effect thedesired furnace movement.

Extending outwardly through the acid lining 30 of medial chamber 25 andopening exteriorly of the furnace 20 is a copper taphole 43 of anydesired construction. Similarly a bronze taphole 44 extends outwardthrough the reducing lining 31 of end chamber 26, as as 44. Anadditional outlet opening or bronze taphole 45 extends outward throughthe reducing lining 32 of end chamber 27 exteriorly of the furnace 20.As best seen in FIG. 1a, the tapholes 43, 44 and 45 are located inspecific angular location about the generally cylindrical furnace 20,for a purpose appearing presently, and are provided with suitableclosure means.

Also apparent in FIG. 1a is the generally annular configuration of eachbarrier or partition wall 23 and 24, generally concentric with thecylindrical furnace 20. The barrier wall 23 is provided with a radialslot 46 extending outward from its central opening toward andterminating adjacent to the interior surface of the furnace, the slot orpassageway 46 thereby affording communication between chambers 25 and26. A similar radially extending slot 47 is formed in partition wall 24extending radially outward from the central opening therein toward andterminating adjacent to the inner lining of the furnace 20 to providecommunication between the chambers 25 and 27. As best seen in FIG. 1a,the slots or passageways 46 and 47 are spaced angularly apart from eachother, and also spaced angularly apart from the tapholes 43, 44 and 45.

Spaced from .the medial-chamber taphole 43, the furnace wall of themedial chamber may be provided with a relatively large side charge door48 facilitating the introduction of materials into the furnace.

While the furnace constructed described hereinbefore may be preferred,it is appreciated that other furnace constructions may also be employedin practicing the method of the instant invention, includingconventional furnace constructions and others which will be describedmore fully hereinafter.

In practice of the instant method, first let us consider the refinementof relatively impure copper scrap, say up to 7% lead and 7% tin. Thescrap, either in solid or molten form, is charged to the acid-linedmedial chamber 25 of the furnace 20 through the charge door 48. Thefurnace is generally horizontal in this condition, as in FIG. 1, and isbeing heated, as by a burner 50 issuing fuel into the furnace throughend opening 21, where the fuel is burned and the exhaust removed throughopposite furnace end Opening 22 and an adjacent flue 51.

A slag is initially charged to the medial chamber 25, and in the instantembodiment may be an alkali-oxide-silicate slag such as Na OSiO or NaO-3.22.SiO The alkalioxide-silicate slag may be completely in solid formas a compound, or glass, or may advantageously be introduced at leastpartially as a compound or glass into the furnace to form a startingpool, where e.g. sand and soda ash are added. Otheralkali-oxide-silic-ates may also be used, such 4 as potassium, calcium,or lithium, and in addition, alkalioxide phosphates and/ or borates canbe used.

With furnace heat sufficient to melt the copper scrap and slag, themolten copper remains on the bottom in contact with the acid lining 30,and the slag floats on top.

The copper is :then oxidized by suitable means, such as blowing air oroxygen, as through a tubular lance or tuyere 52 'into the molten copper.During-the oxidizing procedure it is advantageous to maintain anoxidizing atmosphere in the furnace, as by an excess of oxygen beingintroduced with the fuel at the burner. This condition is illustrated inFIG. 1, and in this condition the tin is effectively oxidized andremoved from the copper to the slag, only a relatively small amount oftin remaining in the copper. Some lead is also oxidized and removed fromthe copper to the slag, and some copper is oxidized into the slag andsome remains in solution in the molten copper. After optimum oxidationof tin, the alkali-oxide-silicate slag is removed from the copper. Thismay be accomplished by any suitable means, but in the instant inventionis quickly and easily achieved by mere tilting of the furnace 20, androtating slot 47 as shown in FIG. 2, to pour the alkali-oxide-silicateslag from the medial chamber 25 through the barrier 24 and slot 47 tothe end chamber 27, where it contacts the reducing lining 32.

During the preceding operation a boron slag, such as boron oxide, hasbeen introduced into the chamber 26. In place of boron oxide thefollowing may be used: alkali-oxide phosphate plain, or alkali-oxideboron phosphate, plain or alkali-oxide silicon phosphate and plainsilicon borates. With the furnace 20 tilted as shown in FIG. 2, rotationof the furnace to locate the slot 46 lowermost for passing theboric-acid slag in to the medial chamber 25. This procedure is shown inFIG. 3.

In FIG. 4 is shown an additional oxidizing step, oxygen being introducedthrough the lance 52. into the copper in medial chamber 2 5 beneath theboron-oxide slag. By this procedure the lead from the copper iseffectively oxidized and removed to the slag, taking place underoxidizing conditions, as noted hereinbefore. Also, the remaining tin andsome copper is oxidized into the slag. Of course, the furnace 20, asseen in FIG. 4, has been returned to a generally horizontal position androtated to locate the slagpassage slots 46 and 47 upward to preventcommunication between the medial and end chambers.

After oxidation and removal of the lead, the boronoxide slag may bereturned to the reducing lining 31 of end chamber 26, as by tilting ofthe furnace 21 and rotating the slot 46 to the position shown in FIG. 5.

Upon return of the furnace 20 to its horizontal position of FIG. 6, themolten copper may contain substantial Cu O, and may be reduced to toughpitch copper or better by the blowing of butane or other suitablereducing gas through a reducing lance 53 into the copper. The boronoxideslag and alkali-silicate slag may also be reduced in their respectivechambers 26 and 27, as by blowing butane and carbon through reducinglances 54 and 55. Any lowsulphur and low-ash carbonaceous material maybe employed, e.g. calcined petroleum coke. This causes the settling outof lead-rich bronze from the boron-oxide slag and settling out oftin-rich bronze from the alkali-oxidesilicate slag. The copper,lead-rich bronze and tin-rich bronze may then be tapped from respectivetapholes 4 3, 44 and 45 upon angular shifting or rotation of the furnace20, as required. For simplicity of illustration in FIG. 7, the bronzeand copper tapholes 44, 45 and 43 are shown in line, but are preferablyangularly spaced for separate tapping operations. Excess lead, beyondsolubility limits, will settle out in the mold, and can be mechanicallyseparated.

The slags remain in their respective chambers, having been rejuvenatedby the reducing actions and removal of bronze. Upon rotation of thefurnace 20 and tilting to pass the alkali-oxide-silicate slag from itschamber 27 to chamber 25, as best seen in FIG. 8, the furnace may berotated and tilted to assume the position of FIG. 9, which is similar tothat of FIG. 1, preparatory to receiving impure copper to be refined. Ofcourse, the copper previously processed may be subjected to repeatedrefining, either by one or both of the slags, should further lead or tinremoval be required. Also, it is appreciated that copper scrap havingrelatively low lead content and relatively high tin content may onlyrequire refining by the alkali-oxide-silicate slag alone; and similarly,copper scrap having relatively high lead and low tin may be refined byuse only of the boron-oxide slag. Then only a two-compartment furnacewould be needed. Also, if the slag was not reduced and returned to thesame copper bath, a rotating only-twocompartment furnace could be usedwithout tilting. Such a furnace could be end charged or side charged,the former without a side door.

Upon removal of more heavily poled copper from the furnace, it has beenfound advantageous to pass the molten copper through a bed ofcarbonaceous material, such as calcined petroleum coke under a reducingatmosphere, say an atmosphere of carbon monoxide, while pouring intoingot molds under reducing conditions, to produce an exceptionallyoxygenand hydrogen-free copper, rather than the usual tough pitchcopper.

Referring now to the embodiment of FIG. there is shown therein atransverse cross-sectional view of a generally cylindrical furnace awhich may comprise a single chamber having open ends, as at 21a, as forthe introduction of burner fuel and egress of combustion products. Theinterior of the furnace 20a is provided with an arcuate segment of acidlining, as at a extending the length of the furnace and through an arcof approximately 200. The acid lining or section 30a may be composed ofat least 70% by weight SiO Extending arcuately from one longitudinaledge of the acid lining 30a. is a section 3111 of reducing lining, suchas carbon-bonded silicon-carbide brick, substantially pure carbon,graphite which may include clay, or other suitable reducing material.The reducing-lining section 31a may extend through the remainder of thefurnace and an arc of approximately 130 at the door cross section withone longitudinal edge proximate to a longitudinal edge of the acid-linedsection 300. Thus, the lining sections 30a and 31a may each beconsidered as concave and arranged in side-by-side relation.

The furnace 20a may be mounted by any suitable means, such as rollers41a extending longitudinally of the furnace, whereby the furnace may beaxially rotated, for purposes appearing presently.

Extending outwardly through the acid-lined section 30a and openingexteriorly of the furnace may be a copper taphole 43a. The coppertaphole 43a is located in spaced relation between longitudinal bounds ofthe acid-lined section 30a. An additional taphole 4461, with suitableclosure means, extends outward through the reducing lining 31a and opensexteriorly of the furnace, being located in spaced relation betweenopposite longitudinal bounds of the reducing lining. In addition, thefurnace 20a is advantageously provided with a charge door 48a, which maybe located between the acid-lined section 30a and reducing lining 31a.As shown in solid lines, the charge door 48a is in an upper region ofthe furnace 20a, as is the bronze taphole 44a. However, the coppertaphole 43a is in a lower-side region of the furnace. In the solid-lineposition illustrated in FIG. 10, with the furnace being heated, impurecopper may be charged through the door 48a, or through the burnerend-door opening either as a solid scrap or in molten condition. Thesolid or molten scrap is thus gravitationally placed on the acid lining30a. For example, let us consider No. 2 copper scrap having a leadcontent of between /2 and 1%, and a tin content of between /2 and 1%.

Under continued furnace-heating conditions slag formers are introducedinto the furnace, which may include plain or alkali-oxide borosilicates,alkali-oxide borophosphate, alkali-oxide phosphate, or plain oralkali-oxide boro-silico-phosphate. The slag-forming material may beintroduced into the furnace either in solid form, the e.g. alkali-oxideborosilicate being a glass, or the alkali-oxide borosilicate glass maybe used to form a starting pool in the furnace and the ingredients addedto the partially liquefied glass. For example, a slag-forming materialcomposed of borax and silica sand may be employed. A particularcomposition of borosilicate and alkali oxide may assume the followingcomposition:

Percent by wt. Si0 80.6 12 0 11.3 A1 0 2 Na O 3.8 K20 .6 CaO .4

Under oxidizing atmosphere, as by injecting excess air at the burner,the scrap is oxidized by blowing air or oxygen with lance or tuyere intothe molten copper. The resultant lead oxide and tin oxide and copperoxide are separated into the slag and some copper oxide remains insolution in the molten copper. Occluded copper prills can be releasedfrom the slag by heating to increase fluidity of the slag and stirring.

The furnace 20a may then be rotated about its axis to place the taphole43a. lowermost, and the copper removed through the taphole, as bypassage through a closed launderer. In the launderer the copper isreduced by injecting butane or other suitable reducing gas into themolten copper to lower the copper-oxide level as required, say below.45% as in tough pitch copper. Further reduction may be achieved asdescribed hereinbefore and followed by passage of the molten copperthrough a carbonaceous bed under a reducing atmosphere.

After the pouring and reduction of the molten copper, the furnace 20amay be axially rotated so that the slag remaining in the furnace isplaced on the reducing lining 31a. The furnace is maintained with areduced atmosphere, as by a rich fuel-air mixture, and the slag blown,as by lance or tuyere with a reducing gas, say butane or a mixture ofbutane with carbon. Sufficient furnace temperature is required tomaintain the slag sufficiently liquid for migration thereof foreffective oxygen removal.

The slag-reducing operation effects separation of bronze from the slag,which bronze may be tapped through the hole 44a. More specifically, slagreduction by butane effects removal of tin-rich bronze from the slag,while slag reduction with butane and carbon effects lead-rich-bronzeremoval. Thus, if it is desired to separately tap the tin-rich bronzeand lead-rich bronze from the slag, the tin bronze may be first removedby reduction with butane alone, and the lead-rich bronze later removedby reduction flushing with a reducing atmosphere, such as with butaneand carbon.

While the bronze thus recovered is of commercial value, the slagreduction serves to rejuvenate the slag for repetition of theabove-described refining procedure.

That is, the furnace 20a may be rotated to assume the initial solid-lineposition shown in FIG. 10 with the slag on the acid lining 30a, and anew charge of copper scrap introduced into the furnace. If desired,copper scrap of initially high lead and tin content may be rerefined tofurther reduce the lead-tin content, if either the copper or slag isremoved from the furnace during said slag reduction and the originalslag may be reused after rejuvenation.

While the tin-removing slags and the lead-removing slags were describedhereinbefore as being used conjointly for highly effective tin and leadremoval, respectively, it is appreciated that these slags may beemployed separately or independently of each other if desired in afurnace like 20a or two furnaces like 20a of FIG. 10 operating intandem. The copper can be duplexed. The scrap is melted in one furnaceand tin oxidized out, and the unfinished copper poured into anotherfurnace. It is there further oxidized for lead removal and then pouredthrough a poling launderer to finished copper mold. The advantage ofthis is that the longest operations, melting and final casting can bedone simultaneously in both furnaces.

Also, it is appreciated that the methods of the present invention may beemployed in conjunction with other apparatus, such as two-compartmentfurnaces, or singlecompartment furnaces without a reducing lining, thelatter requiring removal of the slag for reduction. Under conditionswhere the alkali-oxide-silicate, phosphate, and/ or borate slags areused independently, it is not as essential that the lining be acid fortin-favoring removal. For example, a basic lining portion would be morefavorable for tin removal and more resistant to the more basictinremoval slags.

While rejuvenation of the slag, as described hereinbefore, enables therepeated reuse, the alkali-fluxed borosilicate slag tends to gain SiOand A1 from the acid lining, so that the addition of borax from time totime may be desirable. The same is true for the alkali-oxidefluxed boronphosphate, borate, phosphate, silicon phosphate andsilicon-boron-phosphates which will become complex alkali-fluxedsilico-boron phosphate.

Upon continued reuse of the boron-oxide slag, B 0 may vaporize as H BO(boric acid) and be lost, and the slag may gain SiO from the acidlining, so that the gradual addition of alkali oxides, such as soda ash,which is Na CO and decomposes into Na O, converts the boronoxide slag toalkali-oxide borosilicate slag. B 0 may be added in early stages toreplenish the vaporized H 80 as well as for plain silicon-phosphate,silicon-borate, boronphosphate and boron-silicon-phosphate slags for SiOpickup. Boron phosphate can also be used instead of B 0 Thealkali-oxide-silicate slags may tend to gain SiO from the acid lining,so that their proper proportions may be maintained by periodic additionof alkali oxide. The alkali-oxide-phosphate and/or -borate and/or-silicate slags would gradually become complex silicates, which can alsobe continued to be used by adding alkali oxide and/or alkali-oxidephosphate instead of the borax indicated above.

FIGS. 11-16 are illustrative of a two-compartment furnace operation inaccordance with the instant invention. As best seen in FIG. 11, afurnace is there generally designated 20b, which may be of an elongategenerally cylindrical configuration having its opposite ends open, as at21b and 22b. The furnace 20b may be divided interiorly by a transversewall or partition 23b having a central through hole 60, and provided atone location adjacent to the interior furnace surface with an additionalport 61.

Thus, the interior of furnace 20b is subdivided by par tition 23b into apair of adjacent chambers 62 and 63, respectively opening outwardlythrough furnace ends 21b and 22b. A charge door may be provided throughthe furnace wall of compartment 62, if desired, or the charge may beintroduced through end opening 21b.

The compartments 62 and 63 are each generally cylindrical, and theinterior of compartment 62 is provided with an acid lining 66 interiorlyof the compartment ex tending through an arc of approximately 200, seeFIG. 12. In addition to the acid-lining section 66, the remainder of theinterior of chamber or compartment 62 is lined with a reducing material,such as carbon, as at 67. Similarly, the interior of furnace chamber orcompartment 63 is provided with a cylindrical segment of acid lining 68,see FIG. 13, of approximately 200, and the remainder of the chamber 63is provided with a reducing lining 69, say of carbon. These linings, andtheir arcuate extents are best seen in FIGS. 12 and 13. It will alsothere be appreciated that the acid linings 66 and 68 of respectivecompartments 62 and 63 are out of alignment with each otherlongitudinally of the furnace, as are the carbon or reducing linings 67and 69 of the respective chambers. Further, the reducing linings 67, 69are substantially completely angularly offset from each other, while theacid linings 66 and 68 are partially angularly overlapping. At alocation remote from the port 61, opening through the acid linings 68 ofcompartment 63, there may be formed a copper taphole 70. Also, aleadbronze taphole 73 is provided in chamber 63, and a tin-bronzetaphole is provided in chamber 62. The tapholes may be provided withnecessary closures. Associated with the furnace 20b, adjacent toopposite ends 21b and 22b may be provided a burner 71 and a flue 72, theburner and flue being movable into and out of communicating relationwith their respective adjacent end openings, if desired.

The furnace 20b is suitably mounted, as by mounting means 75, see FIG.14, including rollers 76 affording axial rotation to the furnace, androllers 77 affording transverse rotation or tilting movement to thefurnace.

In accordance with the method of the instant invention, a tin-removalslag, such as sodium-silicate glass or sodium metasilicate may beemployed in one chamber of furnace 20b, say chamber 62, and alead-removal slag may be employed in the other chamber 63, such as boronoxide. The condition shown in FIG. 11 is that where fully treated copperis being bottom-poured through taphole 70 from beneath the lead-removalslag. During this copper removal, copper-bearing scrap is charged intocompartment 62 with the previously reduced tin-removal slag and heatapplied to the furnace as from burner 71 to effect melting of the scrap.The angular position of the furnace 20b in FIG. 14 is such that the acidlining 66 of compartment 62 is lowermost for supporting the copper scrapand slag, while the reducing lining 69 of the compartment 63 islowermost and supporting the lead-removal slag. During treatment of thescrap in chamber 62 with blowing air lance 65 and tin-removal slag toremove tin, the lead-removal slag in chamber 63 is reduced, as by theintroduction of butane and carbon as through a lance 78. The furnace isthen rotated to place lead-bronze taphole 73 lowermost and bronze tappedfrom chamber 63.

Following this the furnace 20b is rotated to place the acid lining 66 ofcompartment 62 downward, and the partially treated copper fromcompartment 62 is poured through port 61 to chamber '63, while thetin-removal slag remains in chamber 62. This is accomplished by tiltingof the furnace 20b, as by rotation about a transverse axis shown in FIG.15. If desired, a dam segment or stop 79 may be placed across thefurnace end opening 22b to prevent removal of material from the chamber63.

Under continued heating, the copper end chamber 63 is treated by theblowing air lance 49 and lead-removal slag, and simultaneously thetin-removal slag remaining in chamber 62 may be reduced, as by theintroduction thereto of butane and carbon, as through a lance 80. Ifdesired, butane may be used alone for predominant tin removal. Thispermits lead build-up in slag to prevent future lead removal. In thiscondition, the furnace 20b has been slightly rotated so that thereducing lining 67 of compartment 62 is lower-most and supporting thetinremoval slag, the acid lining 68 of compartment 63 remaininglowermost and supporting the copper being treated. In this stageadditional oxygen is being introduced into the copper for oxidizingimpurities which are removed into the slag. The furnace is then rotatedto place the tin bronze taphole 74 lowermost and the bronze is tappedfrom chamber 62. From this condition, the furnace 20b is rotated to thecondition of FIG. 11 for removal of refined copper by bottom-pouringthrough taphole 70 and thence through a reducing launder for poling ofcopper.

By way of further example of the instant method, tinremoval slags (thosefavoring removal of tin over lead) may include 3.22 SiO /Na Oalkali-oxide-silicate glass or SiO /Na O alkali metasilicate which aregood for use on starting scrap of up to 1% tin and lead for the former,and starting scrap of up to 1% tin for the latter.

Other satisfactory slags favoring the removal of tin over lead arealkali pyrophosphate, e.g. 2Na O/P O alkali-oxide boryl phosphate, e.g.2Na O/B O /P O and alkali orthosilicate, e.g. 2Na O/SiO and alkalimetaborate, e.g. Na O/B O Additional slag-forming materials which favorremoval of lead over tin, in place of boron oxide, which was good foruse on starting scrap of up to 1% lead, include plain silicoborates,e.g. B O /SiO to SiO /3B O alkali metaphosphate, e.g. Na O/P O or NaPOalkali-phosphate tetraborate, e.g. Na 'O/P O /2B O 15% by weight ofalkali metaphosphate in boron oxide, e.g. 15 by weight of NaPO 85% byweight of B alkali-oxide fluxed silicate phosphate; plain silicylmetaphosphate, e.g.

SiO /P O plain boron phosphate (some people call this boronorthophosphate), e.g. BPO or B O /P O In addition to alkali-oxideborosilicate for use as balanced lead-and-tin-removal slags, which wasgood for use on starting scrap of up to /z% lead and over /2% tin, thereare plain borosilicate, e.g. B O /3SiO and B -O /2SiO etc.; alkali tripolyphosphate, e.g.

alkali oxide boratephosphate, e.g. Na O/B O /P O plain or alkali-oxidesilicatephosphate borate, e.g. 55% BPO /45% SiO Thesilicate-phosphate-borate is good for use on starting scrap of up to 1%lead and 1% tin.

Of course, repeated treatment of the same copper material, as describedhereinbefore, permits use of even higher lead-and-tin-content scrap.

From the foregoing, it is seen that the present invention provides anapparatus for the refinement of impure copper which fully accomplishesits intended objects and is well adapted to meet practical conditions ofuse.

Although the present invention has been described in some detail by wayof illustration and example for purposes of clarity of understanding, itis understood that certain changes and modifications may be made withinthe spirit of the invention.

What is claimed is:

1. In a furnace for refining copper, the combination comprising: acontainer; a first section of refractory lining in said container forcontaining slag and copper material to be refined; a first outletopening through said first. section exteriorly of said container foregress of molten copper; a second section of reducing lining in saidcontainer in fluid communication with said first section; a secondoutlet opening through said second section exteriorly of said container;and mounting means mounting said container for movement to shiftmaterials from said first section to said second section for reducing insaid second section.

2. The combination according to claim 1, in combination with a thirdsection of refractory lining in said container spaced axially thereoffrom said first section; a fourth section of reducing lining in saidcontainer spaced axially from said second section; and a partitioninterposed in the space between said first and second sections and saidthird and fourth sections.

3. The combination according to claim 1, said first and second sectionsbeing in generally side-by-side relation within said container, and saidmounting means mounting said container for angular movement togravitationally shift materials between said sections.

4. The combination according to claim 3, said container being generallycylindrical and said sections being generally arcuate cylindricalsegments, said mounting means mounting said generally cylindricalcontainer for axial rotative movement to angularly shift said segments.

5. The combination according to claim 3, in combination with a thirdsection of reducing lining in generally side-by-side relation with andon the opposite side of said first section as said second section, saidmounting means mounting said container for selective angular movement togravitationally shift materials between said first section and aselected one of said second and third sections.

6. The combination according to claim 5, said container being ofelongate configuration and said sections being arranged in a rowlongitudinally of said container; said mounting means mounting saidcontainer for tilting about a transverse axis and rotative movementabout a longitudinal axis; and barriers in said container intermediateadjacent sections; said barriers having angularly spaced openingsgravitationally passing material through respective openings uponpredetermined tilting and rotative movement, whereby material may bepassed between a selected adjacent pair of said sections while othermaterial is retained in the remaining section.

7. The combination according to claim 2, wherein at least one refractorylining is acid.

References Cited UNITED STATES PATENTS 1,036,500 8/ 1912 Lamb 266-36H2,229,383 1/ 1941 'Lohse 2-6636H 2,641,461 6/1953 Lewis 266-43 3,312,4574/1967 Schweinsberg 'et al. 266-43 GERALD A. DOST, Primary Examiner U.S.Cl. X.R. 26624, 43

